1. Field of the Invention
The present invention relates to a chemical-mechanical polishing (CMP) apparatus. More particularly, the present invention relates to a chemical-mechanical polishing (CMP) apparatus and a method of conditioning a polishing pad capable of improving the polishing effect.
2. Description of the Related Art
With the trend of minimized device dimensions, the resolution of photo-exposure needs to be correspondingly increased. Furthermore, as the depth of a photolithography-exposure reduces, the tolerance for any undulation in the surface profile of the chip is lower. Chemical-mechanical polishing is currently one of the techniques capable of providing global planarization to an ultra-large scale integrated (ULSI) circuit. Aside from planarizing the surface profile of a chip, the anisotropic polishing characteristic of the chemical-mechanical polishing process is applied to fabricate vertical and horizontal metallic interconnects through metal polishing operations, to fabricate shallow trench isolation structures in an front stage manufacturing process or advanced device, to planarize micro-electromechanical system or to fabricate flat panel display.
FIG. 1 is a schematic drawing of a conventional chemical-mechanical polishing apparatus. As shown in FIG. 1, the conventional chemical-mechanical polishing apparatus 100 comprises at least a polishing platen 110, a polishing pad 120, a slurry supplying piping 130, a polishing pad conditioner 150 and a chemical reagent supplying piping 160.
In FIG. 1, the surface of the polishing platen 110 further comprises a plurality of slurry outlets 112. The polishing pad 120 is disposed on the polishing platen 110. The polishing platen 110 drives the polishing pad 120 to spin through a carrier platform (not shown). With the delivery of slurry, a chemical-mechanical polishing process is carried out to planarize a chip or any structure requiring global planarization in a semiconductor fabrication process.
The slurry supplying piping 130 is connected to the bottom of the polishing platen 110. The slurry is delivered from a slurry supplying tank 140 through the slurry supplying piping 130 underneath the polishing platen 110 and the slurry outlet 112 to the surface of the polishing pad 120. Because the polishing agent is slurry, the slurry outlet 112 may be blocked if the concentration of the slurry is too high or some dregs are clogged up in the slurry outlet 112. As a result, a blocked slurry outlet 112 can not deliver slurry to the polishing pad 120 evenly. The non-uniform slurry distribution on the polishing pad may have some effects on the planarity in subsequent chemical-mechanical polishing process. In some cases, defects will be formed in the fabricated devices.
As shown in FIG. 1, the polishing pad conditioner 150 is disposed on the polishing pad 120. The chemical reagent supplying piping 160 is connected between the polishing pad conditioner 150 and a chemical reagent supplying tank 170. The chemical reagent in the chemical reagent supplying tank 170 is delivered to the polishing pad conditioner 150 through the chemical reagent supplying piping 160.
At the end of a polishing operation, slurry dregs sometimes are attached to the surface of the polishing pad 120. When this happens, the polishing pad conditioner 150 can adjust the condition on the polishing pad 120 by removing dregs from the surface of the polishing pad 120. However, the delivering of chemical reagent to the polishing pad conditioner 150 only has a limited conditioning effect on the polishing pad 120.